Attaching structure for a seatbelt apparatus

ABSTRACT

An attaching structure for a seatbelt apparatus of a vehicle equipped with a seat, which is supported by a vehicle body through a weight sensor. The seatbelt apparatus includes a buckle, a seatbelt, and a tang. The buckle is fixed to one side of the seat of the vehicle. One end of the seatbelt is fixed at the vehicle so that it allows a length adjustment of the seatbelt, and the other end of the seatbelt is connected to an anchor that is fixed to the other side of the seat. The tang is provided at the seatbelt and is engaged with the buckle so as to hold an occupant to the seat. Here, the anchor and the buckle are fixed at the position higher than the weight sensor.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an attaching structure for aseatbelt apparatus of a vehicle equipped with a seat, which is supportedby a vehicle body through a weight sensor.

[0003] 2. Description of Relevant Art

[0004] In the conventional three-point support type seatbelt apparatus(hereinafter indicated as seatbelt apparatus), one end of a seatbelt isstored in a retractor, which adjusts the length of a seatbelt byallowing the pull-out/take-up of the seatbelt. The other end of theseatbelt is fixed to a vehicle floor that is in the vicinity of theside-part of a vehicle seat. In this seatbelt apparatus, the seatbelt isguided by a slip guide positioned on a level with a shoulder of avehicle seat.

[0005] The seatbelt has a tang placed between the slip guide and theseatbelt-anchor. When using this seatbelt apparatus, the tang is engagedwith a buckle fixed to the vehicle floor that is in the vicinity of theother side-part of the vehicle seat. Thereby, the occupant sitting onthe seat (vehicle seat) is held by the seatbelt that is supported atthree points (the slip guide, the seatbelt-anchor, and the buckle).

[0006] Generally, the seatbelt is used for holding the occupant on theseat. But, the seatbelt apparatus is also used in order to fix a childseat to the vehicle seat.

[0007] In the conventional seatbelt apparatus, the pull-out and take-upof the seatbelt is managed in compliance with the prescribed operationmode. In other words, the adjustment of the length of the seatbelt ismanaged in compliance with the prescribed operation mode. Here, a term“pull-out” means that the pulling out of the seatbelt stored in theretractor, in order to lengthen the length of the seatbelt. A term“take-up” means that the storing of the seatbelt into the retractor inorder to shorten the length of the seatbelt. As an example of theoperation mode, an emergency lock mode and an auto lock mode can becited.

[0008] Here, the adjustment of the length of the seatbelt is managedbased on the emergency lock mode, when the collision with other vehicleoccurs and the seatbelt is pulled at a speed of more than a thresholdspeed. That is, this emergency lock mode is performed in order toprotect the occupant against injury by holding the occupant by theseatbelt.

[0009] On the other hand, the adjustment of the length of the seatbeltis managed based on the auto lock mode, when fixing the child seat tothe vehicle seat. In this mode, the pull-out of the seatbelt isforbidden and the take-up of the seatbelt is allowed. Thereby, the childseat is firmly fixed at the vehicle seat without causing the stagger ofthe child seat.

[0010] As an example of these types of the seatbelt, the seatbeltapparatus disclosed in Japanese unexamined patent publication JPH11-245753 can be cited.

[0011] Recently, a vehicle seat equipped with a weight sensor thatmeasures a weight of an occupant has been widely spread. These types ofthe vehicle seat are also widely adopted in the intelligent control ofthe equipments of the vehicle.

[0012] When the child seat is fixed to the vehicle seat equipped withthe weight sensor utilizing the auto lock mode, the child seat is pushedagainst the vehicle seat by the tension of the seatbelt (hereinafter abelt tension) that is caused in the region between the seatbelt-anchorand the buckle. In this occasion, since the seatbelt-anchor is fixed atthe lower part of the vehicle body, the child seat is pushed downwardlyby the belt tension.

[0013] In this occasion, since the force (load), which pushes the childseat against the vehicle seat, acts on the weight sensor, the weightsensor also detects the load caused by the belt tension in addition tothe weight of the occupant and the child seat.

[0014] Thus, this may give a lower reliability of the detection resultof the weight sensor. Thereby, the miss operation of the airbag may becaused when the deployment of the airbag is controlled based on thedetection result of the weight sensor.

[0015] Therefore, the attaching structure of a seatbelt apparatus, whichcan prevent the occurrence of the detection error that occurs when theweight of the occupant is measured by the weight sensor, has beenrequired.

SUMMARY OF THE INVENTION

[0016] The present invention relates to an attaching structure for aseatbelt apparatus of a vehicle equipped with a seat, which is supportedby a vehicle body through a weight sensor. In this invention, aseatbelt-anchor is fixed to a member, which is positioned near the seatthan the weight sensor.

[0017] In the present invention having these constructions, theseatbelt-anchor is fixed to a member that is positioned near the seatthan the weight sensor. Thereby, the load caused by the mount of thechild seat is not applied to the weight sensor. Thus, the weight of anoccupant sitting on the seat is accurately measured.

[0018] In the present invention, it is preferable that a buckle, whichis engaged with/disengaged from a tang of the seatbelt apparatus, isfixed to a member positioning near the seat than the weight sensor.

[0019] That is, the buckle, which fixes the seatbelt at the other sideof the seat with respect to the seatbelt-anchor, is fixed to the memberthat is positioning near the seat than the weight sensor. Thereby, sincethe unfavorable load is not applied to the weight sensor, the weightsensor can measure the weight of the occupant more accurately.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a perspective view which looked at the seatbeltapparatus from upper rear direction.

[0021]FIG. 2 is a front view of the seatbelt apparatus.

[0022]FIG. 3 is a side view of the seatbelt apparatus.

[0023]FIG. 4 is a cross-sectional view of the weight detection unit.

[0024]FIG. 5 is an exploded perspective view of the attaching structurebetween the seatbelt-anchor and the base plate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025] The preferred embodiment of the present invention will beexplained with reference to the attached drawings.

[0026] As shown in FIG. 1, a seatbelt apparatus 2 provided at a seat 1of a vehicle includes a seatbelt-anchor 4, a lap belt 5, a retractor 6,a shoulder belt 7, a slip guide 8, a tang 9, and a buckle 10.

[0027] In this seatbelt apparatus 2, one end of the lap belt 5 isconnected to a seatbelt-anchor 4, which is provided at the outside (doorside) in the vicinity of the bottom of the seat 1. The other end of thelap belt 5 is connected to the tang 9, which is engaged to or disengagedfrom the buckle 10. This buckle 10 is provided at the center side in thevicinity of the bottom of the seat 1.

[0028] To be more precise, the seatbelt-anchor 4 is provided at thedoor-side near the bottom of the seat 1. The buckle 10 is provided atthe cabin-center side near the bottom of the seat 1. One end of the lapbelt 5 is connected to the seatbelt-anchor 4, the other end of the lapbelt 5 is connected to the shoulder belt 7 through the tang 9.

[0029] One end of the shoulder belt 7 is connected to a retractor 6provided at under side of a center pillar 3. This retractor 6 allows thepull-out and take-up of the shoulder belt 7 from the retractor 6. Theother end of the shoulder belt 7 is connected to the lap belt 5 throughthe tang 9 after passing through the slip guide 8 disposed at the upsideof the center pillar 3.

[0030] The rear of the backrest of the child seat 11 is provided withbelt insertion-holes 12 and 12, which are formed at both sides in thewidth directions of the child seat 11. When the tang 9, the lap belt 5,and the shoulder belt 7 are passed through the belt insertion-holes 12and 12 and the tang 9 is connected to the buckle 10, the child seat 11is stably placed on the seat 1.

[0031] The retractor 6 is allowed to switch the operation mode betweenan emergency lock mode and an auto lock mode.

[0032] The emergency lock mode is used in order to hold the occupant onthe seat 1 by the seatbelt apparatus 2. In this emergency lock mode,generally, the pull-out and take-up of the shoulder belt 7 from theretractor 6 is allowed in order to permit the change of the sittingposture of the occupant. In this emergency lock mode, on the other hand,the pull-out or take-up of the shoulder belt 7 is forbidden in the eventof the side collision with other vehicle. In other words, the adjustmentof the length of the shoulder belt 7 is allowed in the usual state, butthe adjustment of the length of the shoulder belt 7 is not allowed whenthe shoulder belt 7 is pulled at a speed of greater than a thresholdvalue.

[0033] The auto lock mode is used when mounting the child seat 11 on theseat 1 using the seatbelt apparatus 2.

[0034] In this auto lock mode, the take-up of the shoulder belt 7 isallowed and the pull-out of the shoulder belt 7 is forbidden. Thereby,the child seat 11 is firmly fixed at the seat 1. In other words, theshortening of the length of the shoulder belt 7 is allowed in the usualstate, but the lengthening of the length of the shoulder belt 7 is notallowed in order to fix the child seat 11 to the seat 1 firmly.

[0035] A limit switch 13, provided on the retractor 6, is used fordetecting the present operation mode, such as auto lock mode, by theretractor 6.

[0036] As shown in FIG. 2 and FIG. 3, the seat 1 is fixed to a floor Fof the vehicle body through a weight detection unit 20.

[0037] Plates 15 and 15 that constitute the frame of the seat part ofthe seat 1 are provided at the both sides along the fore-and-reardirections with respect to the seat 1. Each of the plates 15 isconnected to each of movable sliders 32 of the slidable mechanism 30.

[0038] The rail 31, which is a stationary member of the slidablemechanism 30, is fixed on the weight detection unit 20. The weightdetection unit 20 is fixed to the seat-fixing bracket 16. The seat 1 isfixed to the vehicle body by connecting the each of the seat-fixingbracket 16 to the floor F. In other words, the seat 1 is supported bythe floor F, through the slidable mechanism 30, the weight detectionunit 20, and the seat-fixing bracket 16. Here, the rear-side end of theseat-fixing bracket 16 is connected to the floor F through thesub-bracket 17 (FIG. 3).

[0039] As shown in FIG. 4, the weight detection unit 20 is composed of abase plate 21 connected to the seat 1 through the slidable mechanism 30,a bracket 22 acts as a load acceptor, an arm 23 acts as a loadtransmitter, and a sensor bracket 24 acts as a load detector. Here, FIG.4 shows the state wherein the arm 23 and the sensor bracket 24 aredeformed in compliance with a load to be applied to the seat 1.

[0040] The base plate 21 is a long member, which is a U-like shapedmember in sectional viewing. In other words, the base plate 21 is formedby bending the both ends in the width direction of the rectangular plateso that the depression part is formed inside thereof. Here, this bendend part is defined as side-part.

[0041] The base plate 21 accommodates the bracket 22, the arm 23, andthe sensor bracket 24 in the depression part.

[0042] A long-hole 21 a and a pin-hole 21 b are formed at the bothside-parts of the base plate 21. A bracket pin 25, which connects thearm 23 with the bracket 22, is inserted into the long-hole 21 a, and acenter pin 26, which serves as a rotation axis of the arm 23, isinserted into the pin-hole 21 b.

[0043] The bracket 22 is a member of having a wide grounding area at thebottom thereof and receives a load when the load is applied to the seat1. This bracket 22 also has a bracket-hole 22 a through which thebracket pin 25 is inserted in order to connect the bracket 22 to the arm23.

[0044] The arm 23 has side-wall at the end part in the longitudinaldirections of the arm 23. A bracket-hole 23 a, through which the bracketpin 25 is inserted, and a pin-hole 23 b, through which the center pin 26is inserted, are provided on the side-wall. A notched part is formed onthe other end part of the arm 23 so that pair of convection parts 23 cis formed at the sensor plate 24 side of the arm 23.

[0045] The sensor plate 24 has a pair of a displacement part 24 b at theboth sides of a fixing part 24 a. The displacement part 24 b and thefixing part 24 a is connected through a path 24 c, which has a smallerwidth and thickness than both of the displacement part 24 b and thefixing part 24 a. Here, in FIG. 4, only one side of the sensor plate 24is indicated.

[0046] Each path 24 c has two strain gages (not shown) thereon. Theposition where the strain gages are provided is the vicinity of thedisplacement part 24 b and the vicinity of the fixing part 24 a. Here,each of strain gages is joined by electric wiring so that the bridgecircuit is provided.

[0047] The displacement part 24 b is fixed at the convection part 23 cof the arm 23 by a bolt.

[0048] Thereby, when the load is applied to the bracket 22 and the arm23 is displaced, the displacement part 24 b is also displaced.

[0049] In this occasion, the electrical resistances of each strain gagevaries depending on the tensile force (load) and the compressive force(load), which are caused by the displacement of the displacement part 24b. That is, the electrical resistance of the bridge circuit itselfvaries depending on the degree of the variation of the electricalresistance of each strain gage.

[0050] In the present invention, therefore, the amount of displacementof the displacement part 24 b, i.e. the amount of the load (weight) tobe applied to the seat 1 can be obtained by measuring the electricalresistance of the bridge circuit.

[0051] In the present embodiment, it is preferable that the bridgecircuit has a thermistor 25 at the position between the strain gagesthat are placed on the path 24 c.

[0052] The control unit (not shown) that controls the sensor plate 24 isequipped with the CPU and ROM, and is fixed at the seat-fixing bracket16. The control unit supplies an electric current to the bridge circuitsof the weight detection unit 20, and measures the electric current thatis supplied from the weight detection unit 20 after passing through thebridge circuit.

[0053] Then, the control unit computes the variations of the resistancevalue of the strain gage based on the electric current supplied to thebridge circuit and the electric current supplied from the bridgecircuit. Next, the control unit generates the output signal based on theresult of the computing. The output signal is supplied to respectivecontrol unit, such as a control unit of airbag apparatus or a controlunit of an indicator on the instrument panel.

[0054] As shown in FIG. 2 and FIG. 4, when arranging the weightdetection unit 20 to the seat 1, the bracket 22 is positioned atlower-side and the base plate 21 is positioned at the upper-side. Then,the bracket 22 is connected to the seat-fixing bracket 16 and the baseplate 21 is connected to the rail 31.

[0055] In this weight detection unit 20, the sensor plate 24 and the arm23 act as a weight detection sensor. That is, the weight (load) appliedto the seat 1 is measured by the sensor plate 24 and the arm 23.

[0056] As can be seen from FIG. 2, the seatbelt-anchor 4 of the seatbeltapparatus 2 is fixed to the base plate 21 of the weight detection unit20, which is disposed at the outer side (door side) of the vehicle. Theposition where the seatbelt-anchor 4 is fixed is in the vicinity of therear-side end of the base plate 21 (FIG. 3).

[0057] The buckle 10 is fixed to the base plate 21 of the weightdetection unit 20, which is disposed at the center-side (not the doorside) of the vehicle. The position where the buckle 10 is connected isin the vicinity of the rear-side end of the base plate 21 (FIG. 3).

[0058] In the present embodiment, as described above, theseatbelt-anchor 4 and the buckle 10 are fixed to the members, which arepositioning at the seat 1 side than the weight detection unit 20. To bemore precise, the seatbelt-anchor 4 and the buckle 10 are fixed to themembers that do not affect on the weight detection sensor (the sensorplate 24 and the arm 23) of the weight detection unit 20.

[0059] In the present invention, the undesirable load caused by thetensile force (the belt tension) of the lap belt 5 is not added to theweight detection unit 20 (the weight detection sensor), as long as theseatbelt-anchor 4 and the buckle 10 are fixed to the members, which arepositioning at the seat 1 side with respect to the weight detection unit20 (the sensor plate 24 and the arm 23).

[0060] In other words, the undesirable load caused by the tensile forceof the lap belt 5 is not added to the weight detection unit 20, as longas the seatbelt-anchor 4 and the buckle 10 are fixed to the members,such as the base plate 21, the slidable mechanism 30 disposed above thebase plate 21, and the plate 15.

[0061] In the present invention, still furthermore, the detection errorof the weight of the occupant measured by the weight detection unit 20can be minimized, as long as the seatbelt-anchor 4 is fixed to themembers that are positioning near the seat 1 than the sensor plate 24and the arm 23, even if the buckle 10 is fixed at the floor of thevehicle.

[0062] In the present invention, additionally, it is preferable that theseatbelt-anchor 4 is fixed to the movable members (the movable sliders32 or the plate 15) of the slidable mechanism that are positioning athigher position than the slidable mechanism 30. This is because theseatbelt-anchor 4 can slide in compliance with the slide of the seat 1.

[0063] In the present invention, as shown in FIG. 5, the seatbelt-anchor4 is fixed to the base plate 21 through an anchor mounter 33. The baseplate 21 has a bracket mounting surface 21 e, whose surface faces theslanting upward direction when the base plate 21 is provided on thevehicle. A bolt insertion-hole 21 f is bored on the bracket mountingsurface 21 e.

[0064] The anchor mounter 33 is composed of a fastening part 33 a and amounting part 33 b, which are united into a single piece. The fasteningpart 33 a is fitted together with the bracket mounting surface 21 e whenfixing the seatbelt-anchor 4 to the base plate 21. The mounting part 33b is disposed at one end of the fastening part 33 a so that the mountingpart 33 b extends along the base plate 21.

[0065] This anchor mounter 33 is formed by bending a plate member intoL-like shape. The fastening part 33 a has a bolt-hole 33 c, throughwhich a bolt 38 is inserted. The mounting part 33 b has a screw-hole 33d, to which a bolt 39 is screwed in order to fix the seatbelt-anchor 4to the base frame, when fixing the seatbelt-anchor 4 to the base plate21. The seatbelt-anchor 4 has a bolt-hole 4 a through which the bolt 39is inserted.

[0066] In the present embodiment, the seatbelt-anchor 4 is fixed to theanchor mounter 33, by inserting and screwing the bolt 39 in order of: awasher 37, the bolt-hole 4 a, a spacer 36, and the screw-hole 33 d,after arranging each parts in order of: the anchor mounter 33, a spacer36, the seatbelt-anchor 4, and a washer 37.

[0067] Then, the anchor mounter 33 is attached to the bracket mountingsurface 21 e of the base plate 21 by the bolt 38. Thereby, the fixationof the seatbelt-anchor 4 to the base plate 21 is completed.

[0068] In the present embodiment, the seatbelt-anchor 4 is fixed to thebase plate 21 through the anchor mounter 33, which has a fastening part33 a facing the rearward direction with respect to the vehicle body andwhich is easily attached to the base plate 21 from the rearward of thebase plate 21. Thereby, the fixing operation of the seatbelt-anchor 4 tothe base plate 21 is easily performed from the rearward with respect tothe seat 1 by using the tools, such as a driver and a wrench.

[0069] That is, if the seatbelt-anchor 4 is directly attached to theside surface of the base plate, the fixing operation of theseatbelt-anchor 4 to the base plate 21 is disturbed by the weightdetection unit 20 or the like. Therefore, in the present invention, theanchor mounter 33, to which the seatbelt-anchor 4 is mounted and whichis attached to the base plate 21 from the rear-side of the base plate21, is adopted.

[0070] Thereby, the attaching (fixing) operation of the seatbelt-anchor4 to the base plate 21 is easily performed. This is because theseatbelt-anchor 4 is easily attached to the base plate 21 by attachingthe anchor mounter 33 to the base plate 21 from the rearward withrespect to the seat 1, after fixing the seatbelt-anchor 4 to themounting part 33 b of the anchor mounter 33.

[0071] Although there have been disclosed what are the patent embodimentof the invention, it will be understood by person skilled in the artthat variations and modifications may be made thereto without departingfrom the scope of the invention is indicated by the appended claims.

[0072] In the present invention, the seatbelt-anchor 4 may be fixed toany position as long as the seatbelt-anchor 4 is fixed to the members,which are positioning near the seat 1 than the weight detection unit 20.For example, the seatbelt-anchor 4 may be attached to the frame memberof the seat 1 when the weight detection unit 20 is arranged in thecondition that the weight detection unit 20 is upside down with respectto the arranging manner that is shown in FIG. 3.

[0073] In the preset invention, the weight detection unit 20 is fixed tothe stationary member. But the weight detection unit 20 may be fixed tothe movable slider 32. In this case, since the weight detection unit(weight sensor) is positioned at the higher position, theseatbelt-anchor 4 is fixed to the frame of the seat.

What is claimed is;
 1. An attaching structure for a seatbelt apparatusof a vehicle equipped with a seat, which is supported by a vehicle bodythrough a weight sensor, wherein a seatbelt-anchor is fixed to a member,which is positioned near the seat than the weight sensor.
 2. Anattaching structure for a seatbelt apparatus of a vehicle according toclaim 1, wherein a buckle, which is engaged with/disengaged from a tangof the seatbelt apparatus, is fixed to a member, which is positionednear the seat than the weight sensor.
 3. An attaching structure for aseatbelt apparatus of a vehicle equipped with a seat, which is providedon a vehicle body through a weight sensor, wherein the seatbeltapparatus includes: a buckle to be fixed to one side of the seat of avehicle; a seatbelt, one end of the seatbelt is fixed at the vehicle sothat it allows to adjust the length of the seatbelt, and the other endof the seatbelt is connected to an anchor that is fixed to the otherside of the seat; and a tang, which is provided on the seatbelt and isengaged with the buckle so as to hold an occupant to the seat, whereinthe anchor and the buckle are fixed at the position near the seat thanthe weight sensor
 4. An attaching structure for a seatbelt apparatus ofa vehicle according to claim 3, wherein the weight sensor includes adetector which measures a load to be applied to the seat, and anaccommodator which stores the detector at underside thereof, wherein thebuckle is fixed to the accommodator.
 5. An attaching structure for aseatbelt apparatus of a vehicle according to claim 4, wherein the seathas a pair of weight sensors at the both side thereof, wherein theanchor is fixed to the accommodator of the weight sensor, which islocated at the outer side with respect to the vehicle body, the otherend of the seatbelt is fixed to the accommodator of the weigh sensor,which is located at the inner side with respect to the vehicle body. 6.An attaching structure for a seatbelt apparatus of a vehicle accordingto claim 5, wherein the buckle is connected to the accommodator througha bracket, which has a mounting part that allows to fix the bracket tothe accommodator from the rear-side direction with respect to the seat.